TWI409737B - Display devices and driving method therefor - Google Patents

Abstract

Driving schemes are described in which rows (1 to m) are selected one at a time and column data voltages are inverted to provide inversion schemes for display devices comprising pixels (12) arranged in rows (1 to m) and columns (1 to n). The order in which rows are selected is such that a first group of first polarity rows is selected in a first order, a first group of second polarity rows is selected in a second order, a second group of first polarity rows is selected in the second order, and a second group of second polarity rows is selected in the first order, the first order being one of ascending or descending row number order, and the second order being the other of ascending or descending row number order.

Description

Display device and driving method thereof

The present invention relates to display devices including pixels arranged in columns and rows, and driving or addressing methods for such display devices. In particular, the present invention relates to a drive scheme in which the row drive voltage is reversed to provide an inversion scheme.

Liquid crystal display devices are well known and typically include a plurality of pixels arranged in columns and rows.

Conventional pixel systems are addressed or driven as follows. The remaining columns are run from column 1 and in a sequential order by applying a selection voltage to select one of the plurality of columns of pixels at a time. That is, it is sometimes referred to as switching by switching the voltage column. For a display device (eg, an active matrix liquid crystal display device) in which switching of pixels is performed using a thin film transistor, such selection or switching of individual columns is sometimes performed when a switching voltage is applied to a gate of a related column of transistors. Called gate control.

The pixel system in the currently selected column is provided with individual display settings by individual data voltages applied to each row. These data voltages are referred to in the art as names, including data signals, video signals, image signals, drive voltages, and line voltages.

Each of the columns is selected one by one, and an image for displaying a frame to be displayed can be provided as needed during the selection of the columns. The display is then renewed by a further frame displayed in the same manner, and so on.

In addition, the reversal scheme has been implemented in many liquid crystal display devices. According to the known reversal scheme, it uses two data voltages of different polarities (note that these polarities need not be absolutely positive or negative, as long as they can produce a light modulation layer across a particular display device such as a liquid crystal layer. The opposite polarity voltage). The inversion scheme is used to mitigate degradation of the liquid crystal material that may occur in a continuous single polarity operation.

Any given pixel will be given a different polarity in a different frame (usually an interlaced frame), ie the polarity of the pixel is inverted over time.

In addition, in some reversal schemes, the pixels are also inverted in position relative to other pixels, as explained below.

First consider a row of pixels, different pixels are set with different polarities. Typically, pixels that are interleaved to the downstream are supplied with data voltages of different polarities. This is performed by changing the polarity in time with the column selection procedure. If all rows have the same drive voltage polarity distribution (ie, all pixels in a column have the same polarity), the reversal scheme is called a column reversal scheme. However, if different polarities are additionally provided to adjacent pixels in each column, the inversion scheme is referred to as a pixel inversion scheme, a point inversion scheme, or a verifier panel inversion scheme.

Thus, in a pixel or column reversal scheme, the data voltage applied to a given row is inverted each time a new column is selected. However, a disadvantage of using this scheme is that the power consumed due to the reverse of the data voltage applied to one row each time increases the power consumption. Various addressing schemes have been devised to reduce the amount of power consumed by pixel or column inversion by making the number of polarity reversals less than when the column is selected on a conventional sub-column basis.

For example, US-A1-2003/0107544 describes a pixel or column inversion scheme in which the order in the selected columns is such that the first plurality of consecutive columns of the columns to be driven by the first polarity are consecutively ordered. Ground drive, followed by driving the first plurality of consecutive columns of the columns with a second polarity, followed by a second plurality of consecutive columns of the columns to be driven with the first polarity, and so on. WO 03/030137 describes another pixel or column inversion scheme in which the order in the selected columns is such that the two consecutive odd columns are driven sequentially, followed by two consecutive even columns, followed by the second two sequential The odd-numbered columns are followed by the second-ordered even-numbered columns, and so on, and wherein the other second pair of consecutive odd-numbered columns and the second pair of consecutive even-numbered columns in the pair are selected in reverse order. In a separate example, WO 03/030137 describes yet another pixel or column reversal scheme in which the order in the selected column is such that the two consecutive odd columns are driven sequentially, followed by two consecutive even numbers. Columns are selected in reverse order, followed by sequential second-order odd-numbered columns, followed by second-order even-numbered columns but in reverse order, and so on.

However, all of the addressing schemes proposed above to reduce the amount of power consumed by pixel or column reversal are susceptible to being somewhat affected by the introduction of artifacts in the display image, which is temporarily changed in the driving polarity. Occurs everywhere.

A first aspect of the present invention provides a method of driving a pixel array disposed in columns and rows; the method comprising: selecting columns of the pixels column by column; and applying individual data voltages to the pixels each time a column is selected In the row, the polarity of the data voltage applied to a given row is inverted between the first polarity and the second polarity such that the successive columns are driven with data voltages of different polarities; the columns of pixels are selected column by column. The following steps are performed in the following steps: (i) sequentially selecting the columns of the first polarity column of the first group in a first order, the first polarity columns being driven by the first polarity And contiguous columns; (ii) sequentially selecting the columns of the second polarity column of the first group in a second order, the second polarity columns being consecutive columns at the positions driven by the second polarity; The columns of the first polarity column of the first group are staggered with the column positions of the second polarity column of the first group such that they are consecutively connected to a plurality of consecutive positions; (iii) Second order sequentially selects the first polarity column of a second group The columns, the first polarity columns are consecutive columns at the positions driven by the first polarity; and (iv) sequentially selecting a second polarity column of a second group in a first order a column, the second polarity columns being consecutive columns at the locations driven by the second polarity; the columns of the first polarity column of the second group and the columns of the second polarity column of the second group Interlaced in position such that they are joined together to form a plurality of consecutive columns at a position that contiguous with the plurality of first polarity columns of the first group and the second polarity column of the first group; The first order is one of the order of rising or falling number numbers, and the second order is the other of the order of rising or falling number.

Each of the first polarity column or the second polarity column of each group may include three or more columns.

The pixels can be pixels of an active matrix liquid crystal display.

Another aspect of the present invention provides a display driver device for driving a pixel array disposed in columns and rows, the device comprising: a member for selecting columns of the pixels column by column; and a component for use Applying an individual data voltage to the rows of pixels each time a column is selected, the polarity of the data voltage applied to a given row is inverted between the first polarity and the second polarity such that the successive columns are different in position The data of the polarity is voltage driven; the means for selecting the columns of the pixels column by column is adapted to perform the selection of the columns by performing the following steps in the following order: (i) selecting one by one in a first order. The columns of the first polarity column of the first group, the first polarity columns are consecutive columns at the positions driven by the first polarity; (ii) sequentially selecting a first group in a second order The columns of the second polarity column, the second polarity columns being consecutive columns at the positions driven by the second polarity; the columns of the first polarity column of the first group and the first group The columns of the dipolar column are staggered in position so that And (iii) sequentially selecting the columns of the first polarity column of the second group in a second order, the first polarity columns being driven by the first polarity And (iv) sequentially selecting the columns of the second polarity column of the second group in the first order, the second polarity columns being driven at the locations of the second polarity a continuous column; the columns of the first polarity column of the second group are staggered in position with the columns of the second polarity column of the second group such that they are together become a plurality of consecutive columns at a position And continuing to the plurality of first polarity columns of the first group and the second polarity column of the first group; wherein the first order is one of a sequence of rising or falling column numbers, and the second The order is the other of the order of rising or falling numbers.

Each of the first polarity column or the second polarity column of each group may include three or more columns.

Another aspect of the present invention provides a method of driving a pixel array disposed in columns and rows; the method comprising: selecting columns of the pixels column by column; and applying individual data voltages to the pixels each time a column is selected In the row, the polarity of the data voltage applied to a given row is inverted between the first polarity and the second polarity such that the successive columns are driven with data voltages of different polarities; the columns of pixels are selected column by column. The following steps are performed in the following steps: (i) sequentially selecting a column of three or more first polarity columns of a first group in a first order, the first polarity columns being driven by the first polarity And arranging the columns of the first group of three or more second polarity columns in a second order, the second polarity columns being the second polarity Driving the consecutive columns at the positions; the columns of the first polarity column of the first group are staggered in position with the columns of the second polarity column of the first group such that they are together into a plurality of positions Upper continuous column; wherein the first order is rising or falling One of the sequence of numbers, and the second order is the other of the order of rising or falling numbers.

The pixels can be pixels of an active matrix liquid crystal display.

Another aspect of the present invention provides a display driver device for driving a pixel array disposed in columns and rows, the device comprising: a member for selecting columns of the pixels column by column; and a member For applying a separate data voltage to the rows of pixels each time a column is selected, the polarity of the data voltage applied to a given row is reversed between the first polarity and the second polarity, such that the positions are consecutively listed. Voltage-driven data of different polarities; the means for selecting columns of the pixels column by column are adapted to perform the selection of the columns by performing the following steps in the following order: (i) successively selecting in a first order a column of three or more first polarity columns of a first group, the first polarity columns being consecutive columns at the locations driven by the first polarity; and (ii) sequentially in a second order Selecting a column of three or more second polarity columns of the first group, the second polarity columns being consecutive columns at the locations driven by the second polarity; the first polarity column of the first group The columns and the columns of the second polarity column of the first group Interlaced in position such that they are joined together as a contiguous column of a plurality of positions; wherein the first order is one of a sequence of numbers of ascending or descending columns, and the second order is in the order of number of ascending or descending columns The other one.

Another aspect of the present invention provides a display device including a pixel array disposed in columns and rows, and a display driver device as described above.

Another aspect of the present invention provides a driving scheme in which columns are selected column by column and the row data voltage is inverted to provide an inversion scheme for display devices including pixels arranged in columns and rows. The order in the selected column is such that the first polarity column of a first group is selected in a first order, the second polarity column of a first group is selected in a second order, and the first group is selected in a second order. The polarity column is selected in a second order, and the second polarity column of a second group is selected in a first order, the first order being one of a rising or falling column number order, and the second order is The other of the ascending or descending list of numbers.

The inventors have determined that the cause or effect of the aforementioned artifacts is due to parasitic capacitance effects, and the pixels respond to a root mean square voltage (V _{r m s} ) that will tend to change smoothly with the sequence line, but by position The columns are temporarily selected in an unordered order, and the changes in V _{r m s} no longer occur smoothly in the sequence of positions. The inventors have further determined that the human eye is extremely insensitive to changes in brightness between two consecutive positions, and that it has been known that the average brightness on consecutive columns in two positions during the sequence of a plurality of positions remains reasonably fixed (for The drive scheme for a given uniform data level will tend to reduce the level of artifacts introduced by the power-saving driver scheme. These aspects are presented in the various aspects of the invention above.

1 is a schematic diagram of an active matrix liquid crystal display device in which a specific embodiment of the present invention is applied. A display device suitable for displaying a video image includes an active matrix addressed liquid crystal display panel 10 having rows of pixels consisting of m columns (1 to m) having n horizontally arranged pixels 12 (1 to n) in each column. With array arrays. Only a few pixels are displayed for simplicity.

Each of the pixels 12 is coupled to a separate switching device in the form of a thin film transistor (TFT) 11. The gate terminals of all of the TFTs 11 that are coupled to the pixels in the same column are connected to a common column conductor 14, which is supplied with a select (gate) signal during operation. Similarly, the source terminals that are coupled to all of the pixels in the peer are connected to a common row conductor 16 to which a data (video) signal is applied. The drain terminals of the TFTs are each connected to an individual transparent pixel electrode 20 that forms a portion and defines a pixel. The conductors 14 and 16, the TFT 11 and the electrode 20 are carried on a transparent plate, and a second separated transparent plate carries a common electrode for all the pixels (hereinafter referred to as a common electrode). A liquid crystal system is placed between the plates.

The display panel operates in a conventional manner. Light from a source placed on one side enters the panel and is modulated according to the transmission characteristics of pixel 12. The device is driven column by column by scanning the column conductors 14 with a select (gate) signal, so that the columns of the TFTs are sequentially turned on, and the data (video) signals are applied sequentially and in synchronization with the selection signals as needed for Each column of image displays the row conductors of the component to create a complete display frame (image). The order of the columns selected during the scan will be explained below. Using column-by-column addressing, all of the TFTs 11 of the selected column are turned on for a period determined by the duration of the selection signal corresponding to the TV line time during which the video information signal is transmitted to the pixel 12 by the self-conductor 16. When the selection signal is terminated, the TFT 11 of the column is turned off during the rest of the frame period, thereby isolating the pixel from the conductor 16 and ensuring that the applied charge is stored on the pixel until the next time it is equal to the sub-frame period Was addressed.

The column conductors 14 are supplied with a selection signal by a column of driver circuits 20 in a selected order, the column driver circuit 20 including a bit shift register that is controlled by regular timing pulses from a timing and control circuit 21. . In the interval between the selection signals, the column conductors 14 are supplied by the driver circuit 20 at a substantially fixed reference potential. The video information signal supplied to row conductor 16 is from row driver circuit 22 (shown here in a basic form) and includes one or more shift register/sample and hold circuits. The circuit 22 is supplied with a video signal from the video processing circuit 24 and a timing pulse from the circuit 21 synchronized with the column scan to provide a serial to parallel conversion suitable for the column of the panel 10 once addressed.

Other details of the liquid crystal display device (other than the order described below with respect to the polarity of the selected column system and its like) may be as any conventional active matrix liquid crystal display device, and in this particular embodiment, with the United States The liquid crystal display device disclosed in Patent No. 5,130,829 is the same and operates similarly, the contents of which are incorporated herein by reference.

The manner in which the data polarity is varied between the two polarities when the data voltage is applied to the row will now be explained with reference to Figs. 2a and 2b. 2a and 2b each schematically show (not to scale) a pixel 12, which is formed, in particular, by a pixel electrode 20, the common electrode (corresponding portion; represented by reference numeral 32 in Figures 2a and 2b), and The liquid crystal layer (the corresponding portion thereof; denoted by reference numeral 36 in Figures 2a and 2b).

The common electrode 32 is maintained at a fixed reference voltage (8 V in this example) as shown in Figures 2a and 2b. Figure 2a shows the case when a positive polarity data voltage is applied to a pixel. In this example, a voltage of 11 V is applied to the pixel electrode 20 (as shown), assuming a potential difference of +3 V across the liquid crystal layer (refer to the common electrode 32). In this example, this is a positive polarity. In the gray scale display, the magnitude of this potential difference provides a correlated gray scale due to the voltage magnitude dependence of the electrooptic effect of the light modulation layer (ie, liquid crystal layer 36). However, if the display is binary, the magnitude of the potential difference will only correspond to a fully open state.

Figure 2b shows the case when a negative polarity data voltage is applied to a pixel. More specifically, the situation shown is when the required potential difference (3 V) is applied as in the example of Figure 2a. Therefore, in this case, a voltage of 5 V is applied to the pixel electrode, resulting in a required -3 V potential difference across the liquid crystal layer (refer to the common electrode 32).

It should be noted that in FIGS. 2a and 2b, the voltage applied to the pixel electrode 20 (in absolute sense) is the positive electrode. However, the 5 V signal provides a negative polarity across the liquid crystal layer 36, while the 11 V signal provides a positive polarity across the liquid crystal layer 36. Therefore, in this specification, the terms of the data voltage positive and negative polarity are understood to include, for example, the examples described with reference to FIGS. 2a and 2b, and other examples in which the common electrode system is maintained at 0 V, and positive and negative polarity application data. The voltage is indeed positive and negative in the absolute sense and in the sense of the potential drop across the photomodulation layer.

Similarly, although in the example shown in Figures 2a and 2b, the common electrode 32 is maintained at a direct current potential (here, 8 V), in other driving schemes (referred to as a common electrode driving scheme), the common electrode system uses a The square waveform is inverted to drive, and the present invention can be equally performed with these schemes.

This embodiment can be applied to a column inversion scheme or a pixel inversion scheme. It is more convenient to describe these meanings in more detail first. Figure 3 shows a column reversal scheme applied to the above apparatus. Figure 3 shows the polarity of the data voltage (generally indicated by reference numeral 44) for each row of the above device (indicating only the first four rows is apparent) for a frame (here "1" refers to positive polarity and "-1" Refers to the negative polarity as applied to each column number (generally indicated by reference numeral 42). In order to clearly display only the first 16 columns, columns 1-16 are displayed.

For row 1, column 1 is positive, and thereafter the polarity will alternate for consecutive columns, ie column 2 is negative, column 3 is positive, and so on. All other rows (such as rows 2, 3, and 4 shown) have the same polarity as the same column of each row 1. Thus, as can be seen, any given column has the same polarity across all rows, ie, the inversion occurs based on the column, so the term "column inversion" is used to describe this configuration.

Figure 4 shows, on the other hand, a pixel inversion scheme applied to the above apparatus. Figure 4 also shows, for a frame, the polarity of the data voltage (generally indicated by reference numeral 44) of each row of the device (indicating only the first four rows is apparent) (here "1" refers again to the positive polarity" - 1" refers to the negative polarity) as applied to each column number (generally indicated by reference numeral 42). In order to clearly display only the first 16 columns, columns 1-16 are displayed.

For row 1, column 1 is positive, and thereafter the polarity will alternate for subsequent columns, ie column 2 is negative, column 3 is positive, and so on. Up to now this is the same as Figure 3. However, as shown in Figure 4, for row 2, the positive and negative polarities are reversed compared to row 1. This mode is repeated for alternate rows, that is, row 3 is the same as row 1, row 4 is the same as row 2, and so on. Thus, as can be seen, any two adjacent pixels are of opposite polarity, so the term "pixel inversion" is used to describe this configuration.

In another form of pixel inversion (applied to some color liquid crystal displays), three adjacent rows (one for each color red, blue, and green line) have a first polarity for a given column, and then three adjacent rows have Other polarities, and so on.

The case of the above-described columns or pixel inversion schemes has been explained with respect to the polarity applied to a frame. In the secondary frame, the positive polarity and the negative polarity are reversed.

This particular embodiment is equally applicable to any of the above described column or pixel inversion schemes. For the sake of clarity, this particular embodiment will be described only for row 1 (e.g., in Figures 3 and 4).

Figure 5 shows a drive scheme in accordance with a first embodiment. Figure 5 shows, for a frame, the polarity of the data voltage (indicated by reference numeral 44) of a single row of the above device (here "1" refers to positive polarity and "-1" refers to negative polarity) as applied to each column number ( Indicated by reference numeral 42). In order to clearly display only the first 24 columns, column 1-24 is displayed. Figure 5 further shows the temporal order in which the columns are selected, as indicated by time arrow 46. Thus, the first column selected is whose polarity is shown in the leftmost row, ie column 2 is driven with a positive polarity, then column 4 is selected and driven with a positive polarity, and so on. Therefore, it can be seen that the order of selection of the 24 columns shown in FIG. 5 is as follows (where +ve refers to positive polarity and -ve refers to negative polarity): column 2 (+ve), column 4 (+ve), column 6 (+ve), column 8 (+ve) ), column 10 (+ve), column 12 (+ve), column 11 (-ve), column 9 (-ve), column 7 (-ve), column 5 (-ve), column 3 (-ve), column 1 (-ve), column 24 (+ve), column 22 (+ve), column 20 (+ve), column 18 (+ve), column 16 (+ve), column 14 (+ve), column 13 (-ve), column 15 (-ve), column 17 (-ve), column 19 (-ve), column 21 (-ve), column 23 (-ve).

The order of selection of the columns is based on a cluster comprising six columns such that the first group (ie, columns 2, 4, 6, 8, 10, and 12) containing the first six columns to be driven with positive polarity is tied. The ascending column number order (ie, sequential order 2, 4, 6, 8, 10, 12) is selected; the subsequent one contains the second group of the first six columns to be driven with negative polarity (ie, columns 1, 3, 5, 7) , 9 and 11) are selected in the order of descending (ie, reversed) number (ie, sequential order 11, 9, 7, 5, 3, 1); the subsequent one contains the first six columns to be driven with positive polarity. The third group (ie, columns 14, 16, 18, 20, 22, and 24) is selected in the order of decreasing (ie, inverting) the number of columns (ie, sequential order 24, 22, 20, 18, 16, 14). And then a fourth group (ie, columns 13, 15, 17, 19, 21, 23) containing the first six columns to be driven by the negative polarity is in the order of rising numbers (ie, sequentially 13, 15, 17, 19, 21, 23) Choice. The remaining columns of the device, ie, from column 25 forward (not shown in Figure 5), are selected by repeating this cycle: the first positive polarity group containing the next six columns to be driven by the positive polarity is in the ascending column number order Selecting; then, the first negative polarity group including the next six columns to be driven by the negative polarity is selected in descending (ie, reversed) number order; then the first positive polarity group including the next six columns to be driven by the positive polarity is selected. The descending (ie, inverting) sequence number order is selected; then the first negative polarity group including the next six columns to be driven by the negative polarity is selected in the order of the rising column number; and so on.

In the configuration shown in FIG. 1, column driver circuit 20, timing and control circuit 21, row driver circuit 22, and video processing circuit 24 can be considered together to form a display driver device. This display driver device can be adapted in any suitable manner to implement the column selection ordering of this particular embodiment. For example, column driver circuit 20 can be programmed to select columns in the above order, the row driver circuit can be adapted to switch the row polarity as described above, and the video processing circuit can be adapted to supply buffers or memory (not shown), The columns selected for non-equal numerical order are used to store video material, ie, the buffers can store columns 1, 3, 5, 7, when columns 2, 4, 6, 8, 10, and 12 are selected. The video material of 9 and 11 is then used when the columns 1, 3, 5, 7, 9, and 11 are selected after columns 2, 4, 6, 8, 10, and 12, and the stored video material is used.

6 is a flow chart showing the process steps performed by the display driver device in this particular embodiment to provide column ordering and polarity for a single frame shown in FIG. 5 for a column reversal case.

At step S2, column 2 is selected and a positive polarity data voltage is applied to each row. Column 2 is selected by column driver circuit 20 applying a select voltage to column 2. The application of the positive polarity data voltage is as follows. A video signal (i.e., the size of the data voltage to be applied to each row) is provided by the video processing circuit 24, and under the timing control of the timing and control circuit 21, the video signal is connected to the individual row driver at the correct time. Circuit 22 effectively samples each row at the correct time. The positive or negative polarity is controlled and implemented by the combination of the row driver circuit 22 and the video processing circuit 24 under the control of the timing and control circuit 21.

If the row driver circuit 22 only performs column and field reversal, it can supply video signal supply from the video processing circuit 24, the polarity of the video signal being each field (frame) or each field (frame) and each One column was reversed. In this case, video processing circuit 24 performs switching between the two drive voltage polarities.

If the row driver circuit 22 has performed pixel inversion, the video processing circuit 24 supplies the row driver circuit 22 with two sets of video signals. At any time, one of these settings is positive and the other is negative. Signals from one or the other of the two sets of inputs are directed to alternate rows in the display to provide the desired drive polarity. Video processing circuitry 24 may switch the polarity of the two sets of signals column by column and at the end of each field, although this functionality may also be integrated into row driver circuit 22.

In step S4, the secondary column (i.e., column 4) is selected as if it were a secondary sequence of six columns of the first group to which positive polarity is applied, and a positive polarity data voltage is applied to each row.

This process is for the repetition of the remaining columns of the six columns to which the positive polarity is applied (as indicated by the interrupt arrow between steps S4 and S6 in Fig. 6), until step S6, column 12 is selected and positive polarity The data voltage is applied to each row.

In this embodiment, the number of "groups" is six, so the next six columns to be selected will be the negative columns of the first group (ie, columns 1, 3, 5, 7, 9, and 11). . Furthermore, as described above, the group will be selected in descending (i.e., inverted) number order (i.e., 11, 9, 7, 5, 3, 1).

Therefore, at step S8, column 11 is selected and a negative polarity data voltage is applied to each row. Next, in step S10, column 9 is selected and a negative polarity data voltage is applied to each row. This process is repeated for the remaining columns of the six columns of the first group to which the negative polarity is applied (indicated by the interrupt arrow between steps S10 and S12 in Fig. 6) until step S12, column 1 is selected and the negative electrode The data voltage is applied to each line.

The next six columns to be selected will be the positive columns of the secondary group (ie, the second group) (ie, columns 14, 16, 18, 20, 22, and 24). Moreover, as described above, this group will be selected in descending (i.e., reversed) list of numbers (i.e., sequentially, 24, 22, 20, 18, 16, 14).

Therefore, in step S14, column 24 is selected and a positive polarity data voltage is applied to each row. Next, in step S16, column 22 is selected and a positive polarity data voltage is applied to each row. This process is repeated for the remaining columns of the six columns of the second group to which the positive polarity is applied (as indicated by the interrupt arrow between steps S16 and S18 in Fig. 6), until step S18, column 14 is selected and positive polarity The data voltage is applied to each row.

The next six columns to be selected will be the negative columns of the subgroup (ie, the second group) (ie, columns 13, 15, 17, 19, 21, 23). As described above, this group will be selected in the order of rising column numbers (i.e., sequentially 13, 15, 17, 19, 21, 23).

Therefore, at step S20, column 13 is selected and a negative polarity data voltage is applied to each row. Next, at step S22, column 15 is selected and a negative polarity data voltage is applied to each row. This process is repeated for the remaining columns of the six columns of the second group to which the negative polarity is applied (as indicated by the interrupt arrow between steps S22 and S24 in Fig. 6), until step S24, column 23 is selected and negative is positive. The data voltage is applied to each line.

As described above, the remaining columns are selected and the positive or negative polarity is applied to the rows in the iterations of the loops described for columns 1-24, by assigning the columns into a series of six consecutive sequences of a given polarity, followed by The following cycles are selected (and the appropriate polarity data voltage is applied to the rows): the positive polarity column of the subgroup is selected in ascending column number order (the first such display is shown in Figure 6, as in step S26, where The selection column 26 and the positive polarity data voltage are applied to each row), and then the negative polarity column of the subgroup is selected in descending column number order, and then the positive polarity column of the subgroup is selected in descending column number order, followed by the negative polarity of the subgroup Columns are listed in ascending column number order, etc. (indicated by the interrupt arrow between steps S26 and S28 in Fig. 6), until in step S28, the last selected column (i.e., column (m-1); here In a specific embodiment, wherein the display has about 600 columns by 800 rows, then column 599) is selected, and a negative data voltage is applied to each row (the column m of 600 listed here has been selected as the last group) Part of the positive polarity column).

This completes the addressing of this frame. During the addressing of the sub-frame, the positive and negative polarities are reversed, but the columns are selected in the order given above.

In the above process, the column is selected before the voltage is applied to the row. Or, you can reverse this order. Regardless of the order in which it is used, the row voltage is typically maintained until the column has not been selected.

Advantageous effects that are easily achieved by implementing the above-described driving scheme will now be conceptually described with reference to FIG. Fig. 7 is a prediction predicted from a prediction simulation of luminance errors (ordinates) of respective columns with respect to position column numbers (abscissa) for display device driving using the above scheme. It should be noted that for completeness, the display details used for the predictive model need not be the same as the particular display device described above with reference to Figures 1 and 2; however, the predicted results can still be used to assist in interpreting the relevant concepts.

It can be seen from Figure 7 that the change in brightness between two adjacent columns (e.g., column 12 versus column 13) can be quite large. However, the inventors have appreciated that this can be accommodated because the eye is not particularly sensitive to changes in brightness that cancel each other out of adjacent columns. Instead, the inventors have surprisingly introduced this drive scheme by considering the average luminance error for any two-position adjacent column. This average is shown in Figure 7 as an approximate line 100. It can be seen that with the above drive scheme, this average (line 100 in Figure 7) is approximately uniform and smooth in all columns. This result provides a favorable reduction (or tendency to reduce) visible horizontal bands or other artifacts. In particular, groups of six columns of the same polarity can be driven sequentially, thus saving power, but artifacts in the form of clusters of six columns or groups of six columns are removed or At least tend to decrease.

In particular, in the regions of columns 12 and 13, the average brightness (line 100 in Figure 7) is consistent over the large difference in luminance error between column 12 and column 13. This is in particular derived by the example of the selection process described above with reference to Figures 5 and 6, wherein a given group of polarities of a given group (i.e., in the example, the negative polarity column of the first group, ie Columns 1, 3, 5, 7, 9, and 11) and the other polarity of the group in front of it (ie, the positive polarity column of the first group in the example, ie, columns 2, 4, 6, 8, 10 And 12) are driven in the opposite manner of the order of rising or falling numbers, but the other polarity of the group (ie, the positive polarity of the second group in the example, column 14, Driving in the same way as the rise or fall of 16, 18, 20, 22 and 24). In other words, the inference is derived from the first order (which can also be considered as "direction") in the order of the number of ascending or descending numbers in a group of (as previously defined) first polarity columns, and then By selecting columns in the other polarity column of the corresponding group in other orders (directions), then in the order of individual inversion (direction) in the column of the first polarity of the subgroup, and the other polarity of the corresponding subgroup Choose among the columns.

It should be remembered that the scheme has been described in detail for a given frame, however the polarity will be reversed in the secondary frame. Therefore, although the even columns have positive polarity in the above-mentioned frame, the odd columns in the secondary frame will have positive polarity.

Furthermore, various changes can be made to the above addressing scheme while maintaining the basic concepts described in the previous two paragraphs. For example, column 1 can be selected first instead of column 2 in the above example. In this case, the other columns will be selected according to the principles listed above. Similarly, for example, the basic cycles listed above can be used without starting at the beginning of the cycle as described above. For example, in the above-mentioned columns in the first group, the columns are selected in the order of rising column numbers, and in the columns in the subsequent group, different systems are selected in the order of ascending or descending (direction), in the first The columns in a group may be selected in descending order of numbers, wherein the columns in the subsequent group may be selected in ascending or descending order to follow the above concepts. Again, this variation can be introduced to accommodate displays having a number of columns that are not evenly divided into the groups that are expected to be assigned to each group.

Another possibility is that the solution can be applied only to some columns of the display, not to all columns of the display. Alternatively, the display column can be divided into two or more regions, wherein the scheme can be applied to these regions separately.

Another possible change is as follows. In the above-described embodiments, the columns are processed (i.e., sequentially selected) in groups of six consecutive columns that are driven with the same polarity. However, in other embodiments, the number may be different, i.e., the columns may be assigned to any number of groups from 2 as desired. The larger the number, the fewer times each line needs to switch polarity, and thus the more power is saved. However, this involves a compromise because when a larger number is selected, the other polarity columns receive their selection later, and thus any moving artifacts that remain may be more apparent despite the advantages of the present invention. Similarly, driver circuits and/or missing column data buffers become more complex. Therefore, this number can be selected for consideration of such tradeoffs, depending on the particular circumstances, as desired by those skilled in the art.

Other specific embodiments of the above process include examples in which the number of columns in each "group" contains two (and in other examples, depending on the circumstances of any particular system under consideration, the compromise condition, as needed, any higher than two Other numbers). The inventors have further considered having another driving scheme similar to the above process. In summary (for the above example), this further approach can be as in the above example, except that the columns in the positive polarity column of the second group are in the same order (direction) (in the order of rising or falling column numbers) The direction) is selected as in the positive column of the first group; and likewise, the columns in the negative column of the second group are in the same order (direction) (in ascending or descending The direction in the column number order is selected as in the columns in the negative polarity column of the first group. This difference means that since the reversal of the order (direction) between the first and second groups of the same polarity does not occur, a surprising advantage is found in the above scheme. However, the inventors have appreciated that for groups of three or more columns, such further solutions are still superior to prior art drive schemes, i.e., are susceptible to reducing some degree of artifacts.

A specific embodiment of this further drive scheme will now be described with reference to Figures 8 and 9. A specific embodiment of this further driving scheme is performed in the same apparatus described above with reference to Figures 1 through 6, except that the column selection and row address control elements are adapted to control column selection and data polarity addressing as described below. Moreover, this embodiment again uses the various polarities of the six columns of the cluster, but as explained in the previous paragraph, unlike the six columns, other embodiments may use a different number of columns (where the number is three or more) ).

As with the specific embodiments previously described, the specific embodiments described below are equally applicable to any of the above-described column or pixel inversion schemes. For the sake of clarity, this particular embodiment will again be described only for line 1 (as in Figures 3 and 4).

Figure 8 shows a drive scheme in accordance with another embodiment. Figure 8 shows, for a frame, the polarity of the data voltage (indicated by reference numeral 44) of a single row of the above device (where "1" refers to positive polarity and "-1" refers to negative polarity) as applied to each column number ( Indicated by reference numeral 42). For the sake of clarity, only the first 24 columns are displayed, ie columns 1-24 are displayed. Figure 8 further shows the temporal order of the selected columns as indicated by time arrow 46. Therefore, the first column to be selected is whose polarity is shown in the leftmost row, ie column 2 is driven with positive polarity, then column 4 is selected and driven with positive polarity, and so on. Therefore, it can be seen that the order of selection of the 24 columns shown in FIG. 8 is as follows (where +ve refers to positive polarity and -ve refers to negative polarity): column 2 (+ve), column 4 (+ve), column 6 (+ve), column 8 ( +ve), column 10 (+ve), column 12 (+ve), column 11 (-ve), column 9 (-ve), column 7 (-ve), column 5 (-ve), column 3 (-ve), Column 1 (-ve), column 14 (+ve), column 16 (+ve), column l8 (+ve), column 20 (+ve), column 22 (+ve), column 24 (+ve), column 23 (-ve), Column 21 (-ve), column 19 (-ve), column 17 (-ve), column 15 (-ve), column 13 (-ve).

The order of selection of the columns is based on a group of six columns, such that the first six columns (ie, columns 2, 4, 6, 8, 10, and 12) of the first group to be driven by the positive polarity are raised. The number order (ie, sequential order 2, 4, 6, 8, 10, 12) is selected; then the first six columns of the second group to be driven by the negative polarity are included (ie, columns 1, 3, 5, 7, 9, and 11) ) is selected in descending (ie, inverted) number order (ie, sequential order 11, 9, 7, 5, 3, 1); then includes the next six columns of the third group to be driven by positive polarity (ie , columns 14, 16, 18, 20, 22, and 24) are selected in ascending order number order (ie, sequential order 14, 16, 18, 20, 22, and 24); then include fourth to be driven by negative polarity The next six columns of the group (ie, columns 13, 15, 17, 19, 21, 23) are selected in descending (reverse) sequence number order (ie, sequential order 23, 21, 19, 17, 15, 13). . The remaining columns of the device, i.e., advancing from column 25 (not shown in Figure 8), are selected by repeating this cycle.

The sub-positive polarity group including the next six columns to be driven by the positive polarity is selected in the order of rising column numbers; and each of the sub-negative groups including the next six columns to be driven by the negative polarity is decreased (ie, inverted) ) The sequence of numbers is alternated between orders.

9 is a flow chart showing the process steps performed by the display driver device in this particular embodiment to provide column ordering and polarity for a single frame shown in FIG. 8 for a column reversal case.

At step S32, column 2 is selected and a positive polarity data voltage is applied to each row. Column 2 is selected by applying a select voltage to column driver circuit 20 of column 2. The application of the positive polarity data voltage is carried out as previously described with reference to FIG.

In step S34, the secondary column (i.e., column 4) is selected as if it were a secondary sequence of six columns of the first group to which positive polarity is applied, and a positive polarity data voltage is applied to each row.

This process is repeated for the remaining columns of the six columns of the first group to which the positive polarity is applied (indicated by the interrupt arrow between steps S34 and S36 in Fig. 9) until step S36, column 12 is selected and the positive polarity data is selected. The voltage is applied to each row.

In this embodiment, the number of "groups" is six, so the next six columns to be selected will be the negative columns of the first group (ie, columns 1, 3, 5, 7, 9, and 11). . Furthermore, as described above, this group will be selected in descending (i.e., inverted) list of numbers (i.e., 11, 9, 7, 5, 3, 1).

Therefore, at step S38, column 11 is selected and a negative polarity data voltage is applied to each row. Next, in step S40, column 9 is selected and a negative polarity data voltage is applied to each row. This process is repeated for the remaining columns of the six columns of the first group to which the negative polarity is applied (indicated by the interrupt arrow between steps S40 and S42 in Fig. 9) until step S42, column 1 is selected and negative polarity The data voltage is applied to each row.

The next six columns to be selected will be the positive columns of the secondary group (ie, the second group) (ie, columns 14, 16, 18, 20, 22, and 24). Moreover, as described above, in this particular embodiment, the group will be selected (in the same order as all other positive polarity groups) again in the ascending column number order (ie, sequentially, 14, 16, 18, 20, 22, 24). ).

Therefore, in step S44, column 14 is selected and a positive polarity data voltage is applied to each row. Next, in step S46, column 16 is selected and a positive polarity data voltage is applied to each row. This process is repeated for the remaining columns of the six columns of the second group to which the positive polarity is applied (as indicated by the interrupt arrow between steps S46 and S48 in Fig. 9), until step S48, column 24 is selected and positive polarity The data voltage is applied to each row.

The next six columns to be selected will be the negative columns of the subgroup (ie, the second group) (ie, columns 13, 15, 17, 19, 21, 23). Furthermore, as described above, this group will be selected (in the same order as all other negative polarity groups) again in descending (ie, reversed) column number order (ie, sequential order 23, 21, 19, 17, 15, 13). .

Therefore, at step S50, column 23 is selected and a negative polarity data voltage is applied to each row. Next, at step S52, column 21 is selected and a negative polarity data voltage is applied to each row. This process is repeated for the remaining columns of the six columns of the second group to which the negative polarity is applied (indicated by the interrupt arrow between steps S52 and S54 in Fig. 9), until step S54, column 13 is selected and negative polarity The data voltage is applied to each row.

As described above, the remaining columns are selected and the positive or negative polarity is applied to the rows in the iterations of the loops described for columns 1-12, which are assigned to the given polarity of the cluster of six consecutive sequences by assigning the columns Then, select the same according to the following cycle (and apply the appropriate polarity data voltage to the rows): the positive polarity column of the subgroup is selected in the ascending column number order (the first one is shown in step S56 in Fig. 9, where The selection column 26 and the positive polarity data voltage are applied to each row), and then the negative polarity column of the subgroup is selected in descending column number order, and then the positive polarity column of the subgroup is selected in the ascending column number order, followed by the negative polarity of the subgroup The column is selected in descending column number order, and so on (as indicated by the interrupt arrow between steps S56 and S58 in Fig. 9), until step S58, the last selected column (i.e., column (m-11); In this embodiment, wherein the display has about 600 columns by 800 rows, column 589) is selected, and a negative data voltage is applied to each row (the column m at column 600 has been selected as the last Part of the positive polarity of the group, and previously selected Select the odd-numbered columns from m-9 to m-1 (in this odd-numbered column from 591 to 599)).

This completes the addressing of this frame. During the addressing of the sub-frame, the positive and negative polarities are reversed, but the columns are selected in the order given above.

In the above process, the column is selected first and then the voltage is applied to the row. Or, you can reverse this order. Regardless of the order in which it is used, the row voltage is typically maintained until the column is no longer selected.

It should be remembered again that the scheme has been described in detail for a given frame, but the polarity will be reversed in the secondary frame. Therefore, although the even columns have positive polarity in the above-mentioned frame, the odd columns in the secondary frame will have positive polarity.

Furthermore, various changes can be made to the addressing scheme described above while maintaining the basic concept of selecting the columns, wherein the first order (direction) is in the ascending or descending list of numbers (as previously defined) the first polar group Selecting the columns in the column, then selecting the columns by column in the other group of the other polarity (direction), and then continuing for each subsequent pair of a first polarity group and a second polarity group select. For example, in the process described with reference to Figs. 8 and 9, even columns are selected in the order of rising column numbers in each group, and odd columns are selected in descending column numbers in each group. However, in an alternative embodiment, odd columns are selected in the order of rising column numbers within each group, and even columns are selected in descending column numbers order within each group.

The invention can also be applied to other drive schemes than configurations in which the staggered columns are of different polarities, wherein different polarities are applied to different columns in a given row. In this case, the clusters of a given polarity are selected in the order described above.

In the above-described embodiments, the components and operating systems of the display driver device use an analogous example of row driver circuit 22. However, in other embodiments, a digital line driver can be used. In particular, the digital line driver can include a bit shift register and a digital to analog (D/A) converter for each row. In such cases, the display driver device will be adapted as needed.

Finally, while the above specific embodiments are described with reference to a particular liquid crystal display device, it will be appreciated that the column selection of the present invention can also be applied to other liquid crystal display devices and to other types of display devices that require or benefit from reverse polarity drive. For example, in the above specific embodiment, the liquid crystal display device is a transmissive device. However, in other embodiments, the liquid crystal display device can be a reflective device or a transflective device.

10. . . Active matrix liquid crystal display panel

11. . . TFT (thin film transistor)

12. . . Pixel

14. . . Column conductor

16. . . Row conductor

20. . . Column driver circuit / pixel electrode

twenty one. . . Timing and control circuit

twenty two. . . Row driver circuit

twenty four. . . Video processing circuit

32. . . Common electrode

36. . . Liquid crystal layer

42. . . Column number

44. . . Data voltage

46. . . Time arrow

100. . . line

The embodiments of the present invention will now be described with reference to the accompanying drawings in which: FIG. 1 is a schematic diagram of an active matrix liquid crystal display device embodying a specific embodiment of the present invention; FIG. 2a shows a pixel applied to the display device of FIG. Figure 2b shows the negative polarity data voltage of the same pixel applied to the display device of Figure 1; Figure 3 shows the column inversion scheme applied to the display device of Figure 1; Figure 4 shows the display device applied to Figure 1 Pixel reversal scheme; FIG. 5 shows a driving scheme; FIG. 6 is a flow chart showing the process steps performed by the display driver device implementing the driving scheme of FIG. 5; FIG. 7 is based on the luminance error of each column. The prediction of the prediction of the position column number of the display device driven by the driving scheme of FIG. 5; FIG. 8 shows another driving scheme; and FIG. 9 shows the process of implementing the driver device by implementing the driving scheme of FIG. Flow chart of the steps.

42. . . Column number

46. . . Time arrow

Claims (6)

A method of driving an array of pixels (12) arranged in columns (1 to m) and rows (1 to n), the method comprising: selecting one of columns (1 to m) of the pixels (12) at a time; And applying a separate data voltage to the rows (1 to n) of the pixels (12) each time a column is selected, the polarity of the data voltage applied to a given row is inverted between a first polarity and a second polarity So that the consecutive columns in the position are driven by a data voltage of different polarity; one column of the columns (1 to m) of the selected pixels (12) at a time comprises the following steps performed in the following order: (i) according to the first time And sequentially selecting the columns of the first polarity column of the first group, the first polarity columns being consecutive columns in the positions of the columns driven by the first polarity; (ii) according to a second Sorting the columns of the second polarity column of the first group successively, the second polarity columns being consecutive columns at the positions of the columns driven by the second polarity; the first of the first group The columns of the polarity column are interleaved with the columns of the second polarity column of the first group such that they are consecutively connected in a plurality of positions Columns; (iii) successively selecting the columns of the first polarity column of the second group in the second order, the first polarity columns being consecutive at the positions of the columns driven by the first polarity And (iv) sequentially selecting the columns of the second polarity column of the second group in the first order, the second polarity columns being the positions of the columns driven by the second polarity a continuous column; the columns of the first polarity column of the second group and the second The columns of the second polarity column of the group are staggered in position such that they are consecutively a plurality of consecutive columns, the locations of which are followed by the plurality of first polarity columns of the first group and a second polarity column of the first group; wherein the first order is one of a list of rising or falling column numbers, and the second order is the other of the rising or falling column number order. The method of claim 1, wherein the first polarity column or the second polarity column of each group comprises three or more columns. The method of claim 1 or 2, wherein the pixels (12) are pixels of an active matrix liquid crystal display. A display driver device for driving an array of pixels (12) arranged in columns (1 to m) and rows (1 to n), the display driver device comprising: selecting the images (12) at a time a member of one of the columns (1 to m); and a member for applying an individual data voltage to the row (1 to n) of the pixels (12) each time a column is selected, applied to a given row The polarity of the data voltage is inverted between a first polarity and a second polarity such that the successive columns are driven by a data voltage of different polarity; for selecting the columns of the pixels (12) at a time (1 to m) a member of one of the columns, and adapted to perform the selection of the columns (1 to m) by performing the following steps in the following order: (i) sequentially selecting the first polarity of the first group in a first order. The columns of the column, the first polarity columns are consecutive columns at the positions of the columns driven by the first polarity; (ii) the second polarity of a first group is successively selected in a second order Column In the columns, the second polarity columns are consecutive columns at the positions of the columns driven by the second polarity; the columns of the first polarity column of the first group and the second column of the first group The columns of the polarity columns are staggered in position such that they are consecutively a plurality of consecutive columns; (iii) sequentially selecting the columns of the first polarity column of the second group in the second order, And the first polarity column is consecutively arranged at the positions of the columns driven by the first polarity; and (iv) sequentially selecting the columns of the second polarity column of the second group in the first order The second polarity columns are consecutive columns at the positions driven by the second polarity; the columns of the first polarity column of the second group and the columns of the second polarity column of the second group Interlaced in position such that they are contiguous in a plurality of positions, which are contiguous with the plurality of first polarity columns of the first group and the second polarity column of the first group; Wherein the first order is one of a list of rising or falling number numbers, and the second order is a rising or falling column number The other in the order. The display driver device of claim 4, wherein the first polarity column or the second polarity column of each group comprises three or more columns. A display device comprising an array of pixels (12) arranged in columns (1 to m) and rows (1 to n), and a display driver device as claimed in claim 4 or 5.